Re: [PATCH 1/2] onewire: w1-gpio: add ext_pullup_enable pin in platform data

[Daniel Mack <zonque@gmail.com>]

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On 31.07.2012 02:59, Ville Syrjälä wrote:
> On Mon, Jul 30, 2012 at 10:12:39PM +0400, Evgeniy Polyakov wrote:
>> Hi
>>
>> Sorry for long delay
>> [resend with fixed Greg's address :)]
>>
>> On Wed, Jul 25, 2012 at 10:54:29PM +0200, Daniel Mack (zonque@gmail.com) wrote:
>>> In the process of porting boards to devicetree implemenation, we should
>>> keep information about external circuitry where they belong - the
>>> individual drivers.
>>>
>>> This patch adds a way to specify a GPIO to drive the (optional) external
>>> pull-up logic, rather than using a function pointer for that.
>>
>> I do not object against this patch, but I have rather limited knowledge
>> about gpio driver. Patch looks good, feel free to add my
>> Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
>>
>> Greg, please pull it into your tree, if Ville does not object.
> 
> No objections from me.

I take this as an Acked-by:?

> The only cosmetic issue I spotted was 'pdata' being assigned twice in
> w1_gpio_probe().

Right. Amended patch below.


Thanks a lot,
Daniel




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>From 37385d15bbd9dbc637f1e46d962c90be5eeb1409 Mon Sep 17 00:00:00 2001
From: Daniel Mack <zonque@gmail.com>
Date: Mon, 23 Jul 2012 16:36:35 +0200
Subject: [PATCH v2] onewire: w1-gpio: add DT bindings

This patch add DT bindings to the w1-gpio driver, along with some
documentation on how to use them.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Acked-by: Ville Syrjala <syrjala@sci.fi>
---
 Documentation/devicetree/bindings/w1/w1-gpio.txt | 22 +++++++++++
 drivers/w1/masters/w1-gpio.c                     | 48 +++++++++++++++++++++++-
 2 files changed, 69 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/w1/w1-gpio.txt

diff --git a/Documentation/devicetree/bindings/w1/w1-gpio.txt b/Documentation/devicetree/bindings/w1/w1-gpio.txt
new file mode 100644
index 0000000..6e09c35
--- /dev/null
+++ b/Documentation/devicetree/bindings/w1/w1-gpio.txt
@@ -0,0 +1,22 @@
+w1-gpio devicetree bindings
+
+Required properties:
+
+ - compatible: "w1-gpio"
+ - gpios: one or two GPIO specs:
+		- the first one is used as data I/O pin
+		- the second one is optional. If specified, it is used as
+		  enable pin for an external pin pullup.
+
+Optional properties:
+
+ - linux,open-drain: if specified, the data pin is considered in
+		     open-drain mode.
+
+Examples:
+
+	onewire@0 {
+		compatible = "w1-gpio";
+		gpios = <&gpio 126 0>, <&gpio 105 0>;
+	};
+
diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
index dac88ff..6012c4e 100644
--- a/drivers/w1/masters/w1-gpio.c
+++ b/drivers/w1/masters/w1-gpio.c
@@ -14,6 +14,8 @@
 #include <linux/slab.h>
 #include <linux/w1-gpio.h>
 #include <linux/gpio.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
 
 #include "../w1.h"
 #include "../w1_int.h"
@@ -42,12 +44,55 @@ static u8 w1_gpio_read_bit(void *data)
 	return gpio_get_value(pdata->pin) ? 1 : 0;
 }
 
+#ifdef CONFIG_OF
+static struct of_device_id w1_gpio_dt_ids[] = {
+	{ .compatible = "w1-gpio" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
+
+static int w1_gpio_probe_dt(struct platform_device *pdev)
+{
+	struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+	struct device_node *np = pdev->dev.of_node;
+	const struct of_device_id *of_id =
+			of_match_device(w1_gpio_dt_ids, &pdev->dev);
+
+	if (!of_id)
+		return 0;
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	if (of_get_property(np, "linux,open-drain", NULL))
+		pdata->is_open_drain = 1;
+
+	pdata->pin = of_get_gpio(np, 0);
+	pdata->ext_pullup_enable_pin = of_get_gpio(np, 1);
+	pdev->dev.platform_data = pdata;
+
+	return 0;
+}
+#else
+static int w1_gpio_probe_dt(struct platform_device *pdev)
+{
+	return 0;
+}
+#endif
+
 static int __init w1_gpio_probe(struct platform_device *pdev)
 {
 	struct w1_bus_master *master;
-	struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+	struct w1_gpio_platform_data *pdata;
 	int err;
 
+	err = w1_gpio_probe_dt(pdev);
+	if (err < 0)
+		return err;
+
+	pdata = pdev->dev.platform_data;
+
 	if (!pdata)
 		return -ENXIO;
 
@@ -151,6 +196,7 @@ static struct platform_driver w1_gpio_driver = {
 	.driver = {
 		.name	= "w1-gpio",
 		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(w1_gpio_dt_ids),
 	},
 	.remove	= __exit_p(w1_gpio_remove),
 	.suspend = w1_gpio_suspend,
-- 
1.7.11.2